The reduction of engine wear in internal combustion engines is a continuing problem. Many engine wear problems are addressed through the use of appropriate lubricating oil applications. However, engine wear reduction also often necessitates the formulation of fuels such as diesel fuel and gasoline with enhanced lubricity characteristics. The present invention provides a solution to the problem of reducing engine wear by providing a fuel additive combination that enhances the lubricity characteristics of fuels such as diesel fuel, gasoline, and the like.
U.S. Pat. No. 5,089,029 discloses a fuel oil composition which comprises fuel oil and 0.1 to 50,000 ppm of an additive compound having the formula EQU R--O--(AO).sub.m --(C.sub.3 H.sub.6 NH).sub.n H
in which R is a hydrocarbyl radical having 10 to 50 carbon atoms, A is an alkylene group having 2 to 6 carbon atoms, m is an integer of 10 to 50, and n is an integer of 1 to 3.
U.S. Pat. No. 5,660,601 discloses fuels for gasoline engines which contain small amounts of polyetheramines represented by the formula EQU R.sup.1 --(OBu).sub.n --NR.sup.2 R.sup.3 (I)
where: R.sup.1 is C.sub.2 --C.sub.30 -alkyl; R.sup.2 and R.sup.3, independently of one another, are each hydrogen, C.sub.1 -C.sub.6 -alkyl, aminoalkylene of the general formula EQU --R.sup.4 --NR.sup.5 R.sup.6 (II)
or polyaminoalkylene of the general formula EQU --R.sup.4 --NR.sup.5).sub.m --R.sup.6 (III)
where: R.sup.4 is C.sub.2 -C.sub.10 -alkylene; R.sup.5 and R.sup.6, independently of one another, are each hydrogen or C.sub.1 -C.sub.6 -alkyl; m is from 2 to 8; and Bu is a butylene radical derived from butylene oxide and n is from 12 to 28.